SIPs - Creating Added Value for Modular Builders

by Corey Nigh

Five decades ago, people had very different ideas about what the future (now) would look like. They dreamed of flying cars and plastic houses, and their concerns about housing centered on a growing population. Fast forward to today’s central focus: energy efficiency. With concerns over energy, SIPs have been receiving a lot of attention from builders, both residential and commercial, due to their contribution in creating strong, energy efficient buildings. 

The main components of a Structural Insulated Panel (SIP) are the facing (most commonly OSB), glue and an insulating core (most commonly expanded polystyrene). One piece of facing material has glue applied, followed by a block of polystyrene. More glue is then applied to the polystyrene, followed by another piece of facing. These three items are placed under intense pressure while the glue cures. This process creates a composite panel product that incorporates and enhances the strengths of its individual components.

Many modular home builders still use traditional construction methods to build homes. These traditional methods involve first, framing in the structure, then having to go back and insulate, then going back over the structure again to add the wall sheathings, usually engineered wood panels and drywall.  While changing their construction process and redesigning plans and the construction process can add cost initially, the long term savings in labor costs by avoiding the repeated back and forth to add additional materials will more than offset the cost.  An added value of SIPs, in particular, is their contribution to energy efficiency for the home owner going forward, creating an even happier customer.

With the release of the 2015 IECC, modular home builders will have to make some changes to their construction practices, such as using alternative materials. Making a change to any type of manufacturing process can potentially be a costly endeavor, and especially so for a product the size of a house. Since modular builders will be dealing with refitting costs so their product remains code compliant, it is a great time to move into utilizing SIP panels!

The building code includes specific manufacturing and installation practices (such as in Section R610 of the 2015 IRC) for SIPs. For example: all SIPs must be manufactured under a quality control program verified by an approved third-party quality assurance agency. Additionally, each panel must be identified by a certificate of inspection or grade mark issued by the agency to ensure code compliance. If the SIPs do not have these grade marks or certificates, you should request the manufacturer to provide panels with these marks or consider finding a new source for your structural insulated panels.

If you are looking for a SIP manufacturer, make sure you look through NTA’s certification directory. Manufacturers with an NTA Listing Report identify their product with an NTA Certification Mark. The NTA Certification Mark is evidence of compliance to the highest standards, showing their product has met the strict guidelines of an in-plant quality control system and has completed testing to building code requirements.

As you are a home builder, you may have questions about SIP product certification reports and what they mean for you, NTA can help you with these questions. Feel free to contact us today.